[3437] Bind to any address when joining multicast group.

src/lib/dhcp/iface_mgr_bsd.cc

@@ -156,10 +156,9 @@ IfaceMgr::openMulticastSocket(Iface& iface,
                               const uint16_t port,
                               IfaceMgrErrorMsgCallback error_handler) {
     try {
-        // This should open a socket, bound it to link-local address
+        // This should open a socket, bind it to link-local address
         // and join multicast group.
-        openSocket(iface.getName(), addr, port,
-                   iface.flag_multicast_);
+        openSocket(iface.getName(), addr, port, iface.flag_multicast_);
 
     } catch (const Exception& ex) {
         IFACEMGR_ERROR(SocketConfigError, error_handler,

src/lib/dhcp/pkt_filter_inet6.cc

@@ -42,7 +42,13 @@ PktFilterInet6::openSocket(const Iface& iface,
         addr6.sin6_scope_id = if_nametoindex(iface.getName().c_str());
     }
 
-    memcpy(&addr6.sin6_addr, &addr.toBytes()[0], sizeof(addr6.sin6_addr));
+    // In order to listen to the multicast traffic we need to bind socket
+    // to in6addr_any.
+    if (join_multicast && iface.flag_multicast_) {
+        memcpy(&addr6.sin6_addr, &in6addr_any, sizeof(addr6.sin6_addr));
+    } else {
+        memcpy(&addr6.sin6_addr, &addr.toBytes()[0], sizeof(addr6.sin6_addr));
+    }
 #ifdef HAVE_SA_LEN
     addr6.sin6_len = sizeof(addr6);
 #endif